Conventionally, a casting mold such as a core of a predetermined shape is generally molded by stirring a particulate aggregate such as casting sand and an additive(s) such as a binder, surfactant, water, and the like with a stirring device to yield an admixture, and then packing the admixture into a cavity within a forming mold. A stirring device generally includes a stirring tank into which the particulate aggregate and the additive(s) are introduced, and stirring blades that are rotated within the stirring tank. In a general configuration of stirring blades, panel-shaped stirring blades 2′ are provided around a rotating drive shaft 23′ connected to a motor as shown in FIGS. 9 and 10.
For example, PCT International Publication No. WO 2005/089984 A is known as a conventional technology related to a mold-making device. As an example of a device for molding a casting mold in which a casting mold is molded by using a water-soluble binder as a binder for a particulate aggregate and hardening the water-soluble binder by heating it to evaporate any moisture therein, WO 2005/089984 A discloses a device including a cylinder extending in an up-down direction, a plunger disposed in the cylinder so that it can move up and down, and a gate for opening and closing an opening at the bottom end of the cylinder, in which the cylinder, plunger, and gate are provided such that they can be raised and lowered and constitute a means for injecting a fluid particulate aggregate into a metallic mold, and a mixer that obtains the fluid particulate aggregate is connected to an opening disposed at the center of the cylinder (Paragraphs [0002] and [0003]).
WO 2005/089984 A also discloses a device for molding a casting mold that includes the following: an admixture storage means that functions as a stirring tank and as an injection tube, a stirring blade mechanism that stirs and foams a particulate aggregate, a water-soluble binder, and water within the admixture storage means, a plugging means that blocks an injection hole of the admixture storage means, and a compression mechanism that compresses the admixture within the admixture storage means to inject the admixture into a cavity of a horizontally-divided metallic mold from the injection hole of the admixture storage means (Paragraphs [0018] to [0021]).
In the procedure for molding a casting mold using the device for molding a casting mold disclosed in WO 2005/089984 A, after closing the injection hole by the plugging means, the particulate aggregate, the water-soluble binder, and the water are introduced into the admixture storage means, the stirring blades of the stirring blade mechanism are rotated to stir and foam the particulate aggregate, the water-soluble binder, and the water to produce an admixture. Next, the stirring blades of the stirring blade mechanism are raised up and the plug of the plugging means is removed from the injection hole to open the injection hole, and then the admixture storage means is transported directly above the horizontally- and vertically-divided metallic mold that has been heated up. Subsequently, an upper metallic mold is placed on a lower metallic mold and then the admixture storage means is placed on the upper metallic mold or the vertically-divided metallic mold, or a stationary mold and a movable mold are closed and a lower surface of the admixture storage means is abutted to an upper surface of the metallic mold. A piston of the compression mechanism is then lowered, and after air between the piston and the admixture is discharged from an air vent hole while the piston is being lowered, a top end opening of the air vent hole is closed with a valve means (not illustrated). Thereby, the admixture within the admixture storage means is compressed so as to inject and pack the admixture into a cavity of the horizontally-divided metallic mold (Paragraphs [0031] to [0034]).